The objective of this study is to develop a means of detecting and recording interictal paroxysmal abnormalities (epileptiform) in the EEG of patients who have suffered a clinical convulsion. Routinely, a 20-30 minute electroencephalogram, which includes hyperventilation and photic stimulation, will detect interictal EEG abnormalities in 30-50% of the patients who suffer convulsions; there remains the other 50% of the patients who are at risk for recurrent convulsions and may suffer the onset of epilepsy. Traditionally these patients must await recurrence of seizures to make a diagnosis, or repeating EEG determinations in the hope of catching an interictal abnormality. If such patients could be detected they could be treated to prevent seizure occurrence without treating those patients who will not have a recurrence.